Is my headache caused by caffeine withdrawal?

I have had a cup of coffee every day for years. I would, at the most, miss a day here and there.

Recently I decided to buy a tub of Japanese matcha tea and replace my daily coffee with a milky matcha latte - just for heck of it.

Two or so days later, I felt a throbbing headache around my eyes, eyebrows and temples that got worse as the afternoon progressed. During the following mornings I would forget all about it as I enjoyed my matcha latte until, again, it got worse each afternoon. This had been going on for what feels like weeks.

Could this be the result of not drinking my daily coffee? Or is it something else?

What contains caffeine?

Caffeine is often said to be one of the most commonly and frequently ingested pharmacologically active, specifically psychoactive, substance in the world.^1,2,3,4 It is a product of plants, most well known for it’s occurance in Camellia sinensis (the tea plant) and Coffea species (coffee).⁵ It is also present in Theobroma cacao (the cacao or cocoa plant), Paullinia cupana (Guaraná) and Citrus (such as Citrus sinensis), as well as others.^5,6 Caffeine synthesis in plants is said to have evolved at least five times independently (an example of convergent evolution)⁵ and is found concentrated, in different amounts, in various parts of plants such as seeds, leaves and flowers.⁶ It is suggested that caffeine acts as part of a chemical defense system that plants use against herbivores and pathogenic microbes.^7,8

How does caffeine interact with the body and what are it’s effects?

The caffeine molecule is a purine alkaloid that is chemically similar to adenine. Adenine can bind to ribose sugar and become adenosine. As well as being one of our RNA nucleosides and a component of AMP, ADP and ATP, adenosine is also a ligand for adenosine receptors, a type of G protein-coupled receptor.⁹ It is due to these receptors that when we consume caffeine we experience the characteristic feeling of wakefulness.

When we drink a cup of coffee or tea, for example, the caffeine travels through our blood, crosses the blood-brain barrier¹ and, due to the similar chemical structure, can bind to receptors in the brain that usually bind adenosine. There are four adenosine receptor subtypes that are known: A₁, A_2A, A_2B and A₃.⁹ Caffeine, binding with a higher affinity to A₁ and A_2A, blocks adenosine from being able to bind and prevents the normal functioning (it’s an antagonist) of the receptor by competitive inhibition.¹⁰

In the nervous system, activation of A₁ receptors, which are concentrated on presynaptic nerve terminals, inhibit neurotransmitter release, regulate cortical activity and contribute to making us feel sleepy.¹⁰

In the brain, A_2A receptors are concentrated in regions of dopaminergic neurons important in aspects of motor function. Most of the biochemical and behavioural effects of caffeine have been related to it preventing normal adenosine inhibition of striatal dopamine transmission.¹⁰

In the liver, by cytochrome P450, caffeine is metabolised into paraxanthine, theobromine and theophylline.²

Downstream effects of this receptor antagonist activity, in the brain as well as other parts of the body, and the body’s metabolism of caffeine¹¹ lead to other effects associated with caffeine consumption, such as vasodilation,^3,4 vasoconstriction,^{1,2,3,4,12,13}, lipolysis^13,14, glycogenolysis in muscle, glycogenesis in liver,¹³ inhibition of phosphodiesterase enzymes,^3,4 reduction of cytoplasmic Ca²⁺ in the vascular smooth muscle cell (VSMC) through cyclic adenosine monophosphate (cAMP), the increase of cytoplasmic Ca²⁺ in the endothelial cell, favoring the synthesis of nitric oxide (NO),³ and effects to circadian timekeeping.^15,16

Some negative effects of caffeine exist, mostly as a consequence of consuming larger or more frequent amounts, including restlessness, anxiety, insomnia, diuresis, irritability, muscle tremor, headaches, cardiovascular symptoms, gastrointestinal complaints ¹ and dependence.^4,17

Caffeine withdrawal

As physiological addiction or dependence can occur from consuming caffeine, it is possible to suffer withdrawal symptoms. When habitual caffeine consumers stop consuming caffeine symptoms experienced include headache, fatigue, flushing, flu-like symptoms, anxiety, apathy, weakness, muscle tension, tremor, difficulty concentrating and nausea.^3,4,18

The headaches are proposed to be caused by the fact that chronic blocking of adenosine receptors by caffeine causes an upregulation of the adenosine receptors. Upon ceasing caffeine use, more of these receptors lead to an increased vasodilation effect when adenosine binds to them.^2,3

Are my headaches caused by caffeine withdrawal?

Before swapping to a matcha latte, my daily caffeine intake consisted of one cup of coffee made at home in the morning. I would use the pour-over drip filter method and use about the same amount of ground coffee beans as this study¹⁹ uses for a “strong” coffee: 6.9g of ground coffee per 100mL, which contained 118mg of caffeine per 100g of filtrate.

Severity of withdrawal headaches increase with the amount of daily caffeine consumed.¹⁸ There are references to withdrawal lasting from two to nine days¹⁸ (internet blog posts say days, weeks and even months). So as my headaches have lasted a few weeks, it remains in question whether or not they are caused by caffeine withdrawal, even though they seemed to have come on since ceasing my daily cup of coffee.

Some suggest lowering caffeine intake instead of completely eliminating it to avoid withdrawal symptoms. However, my headaches seemed to come on when I had a green matcha teas which had a lower amount of caffeine than my coffees. Did I need to lower my caffeine intake more gradually perhaps?

It is also mentioned that withdrawal headaches can disappear upon even a small amount of caffeine being consumed again.¹⁸ I would sometimes break my ”caffeine fast“ and have a coffee on special occasions (where I felt the coffee high I haven’t felt in a while) but my headaches still came back as bad as ever in the afternoons. It only notibly got better upon completely ceasing caffeine consumption. On the second day of having no caffeine, my usual headache did not occur, it was only slight pressure, and was shorter with each passing day. On the fourth day of not having any caffeine at all I also noticed I was able to wake up earlier without feeling tired. This could, of course, just have been a coincidence and my headaches may have got better by this time anyway. My experience is one subjective data point.

Headaches caused by caffeine or the withdrawal of caffeine occur but was mine one? Maybe, maybe not.

See a doctor

Ultimately, if your headaches don’t go away or if you are worried at all, see a doctor.

References